How to get songs from itunes to iphone?

I have tried syncing it hundreds of times but it won't work! I have music on my itunes on my computer that i want to get onto my iphone (from a cd) but no matter what i do i can't get the music onto my phone! Its so frustrating.
iv tried making playlists but it still just won't work. Can someone please tell me what to do?

If your device was synced to a different formatted computer first, e.g., PC then Mac, you would have to reformat your device. And I've also experienced problems syncing on same formatted computers, e.g., Mac and then another Mac. Make sure to update your iTunes and your Apple devices to the latest versions.